1. Field of the Invention
The present invention relates to a direct-contact type hot water heater in which the water, scattered and coming down from above, is designed to flow down along the surrounding side walls of a high-temperature gas feed chamber in the form of a water film without coming down into the feed chamber, whereby, even when fuel is burned in the feed chamber, the efficiency of combustion is improved and the side walls of the feed chamber are prevented from burning off.
2. Statement of the Prior Art
Hithereto, there has been known from Japanese Utility Model Publication Nos. 38-15983, 43-31828 and 43-31833 as well as Japanese Patent Publication No. 37-17440, the technology relating to the direct-contact type hot water heaters of the structure wherein a high-temperature gas feed chamber is provided above a hot water reservoir located on the lowermost portion and an endothermic chamber filled therein with an endothermic material is provided above the high-temperature gas feed chamber so as to bring the water, which is scattered on the endothermic material from above the endothermic chamber and is coming down, into direct contact with a combustion gas resulting from the combustion of fuel in the high-temperature gas feed chamber and thereby obtain hot water of a desired temperature in the lowermost hot water reservoir.
Such direct-contact type hot water heaters excel extremely in thermal efficiency owing to their structure that the water to be heated comes into direct contact with the combustion gas in the course of flowing from the endothermic chamber located above the high-temperature gas feed chamber down into the lowermost hot water reservoir. Moreover, such direct-contact type hot water heaters-can easily be used even at home owing to the system in which water is heated at atmospheric pressure, unlike the conventional boiler system for obtaining hot water in a closed vessel. Additionally, they provide hot water which is free from dissolved oxygen and is thus effective in view of rustproofness. Morever, carbon dioxide contained in the combustion gas is entrapped in the hot water, which means that, when the hot water is used for bathing, it produces an excellent effect such as refreshment which is not attained with hot water obtained by heating usual service water by means of a bath heater. Thus, direct-contact type hot water heater according to the present invention is expected to find a wide use.
However, the conventional direct-contact type hot water heaters are disadvantageous in that their structure is complicated, their installation cost is high, or the combustion gas generated by the combustion of fuel in the combustion chamber does not smoothly flow upwardly. This latter disadvantage can be due to the fact that a perforated plate for supporting the endothermic material filled above the high-temperature gas feed chamber is formed of a horizontally arranged flat plate, a network member depends from the lower end of an umbrella-like member having no vent, as disclosed in Japanese Utility Model Publication No. 38-15983,or umbrella-like members called the flame-dispersing members are supported at intervals in a multi-staged manner or an umbrella-like member is louvered into a complicated shape so as to prevent water from coming down thereon, as disclosed in Japanese Patent Publication No. 37-17440.